Emit feature:click on the bus for every vector feature click

[BhattaraiSijan]

Summary

Adds a single generic bus event, feature:click — fired for every click on a vector feature, on any layer type (classic GeoJSON, vector tile, engine-adapter) and either engine. Payload: { feature, layerName (uuid), latlng, pixel }.

Unlike feature:active it carries no selection semantics and stays independent of the legacy Kinds/Info flow. Unlike map:featureClick it never fires for empty-space clicks and covers mission-config layers, not just adapter-created ones. All three click pipelines in Map_.js funnel into one emit function, so the name and payload are defined in exactly one place.

Documented in the Event-Bus API page. First consumer is the FetchTimeseries plugin (see merge order below).

Known edge

A single physical click on a classic mission feature that also sits over an adapter-created layer emits two feature:click events (one per pipeline, different layerNames). Contained in practice — consumers filter by layer — but worth knowing when debugging.

Merge order

1. this PR → development
2. SeriesChart: chart-series contract and single-variable chart plugin #293 SeriesChart (independent of this one)
3. FetchTimeseries: feature clicks to chart-series events #294 FetchTimeseries (needs this event at runtime; no compile dependency)

Testing

Manual: window.mmgisAPI.on('feature:click', console.log) then click features on a Leaflet-classic mission layer, a vectortile layer, and a deck.gl GeoJsonLayer — one event each, identical shape. Full unit suite green (1040).

[BhattaraiSijan]

Addressed the review findings on this PR:

• Two quick clicks on a vector-tile layer could emit feature A with B's location — the debounce now snapshots the clicked feature at click time so the pair always matches.
• The disableLayerInteractions guard only covered the classic path — moved it (plus the no-feature check) into the emitter itself so all three click paths behave the same.
• The vector-tile path never sent a pixel and deck.gl clicks with no coordinate reported lat/lng 0,0 — pixel now passes through the debounce, and missing coordinates emit null instead.
• The payload handed out a live reference to the map's internal feature — it now emits a snapshot copy (properties cloned, deck.gl's lazy geometry getter preserved).
• layerName could carry a plugin's private layer id on the engine path — it now resolves through asLayerUUID everywhere, so it's always the mission layer uuid or null.
• The docs row promised more than the code did — rewritten to match actual behavior (2D engines only, programmatic selection also fires, nullable fields).
• Zero tests on the event — extracted the payload builder into a pure module and added 7 specs covering the snapshot, copies, and null shapes.